1. Field of the Invention
The invention relates to a novel process for producing organofunctional polysiloxanes in high yields by the addition reaction of an allyl compound and an organohydrosiloxane and relates to novel compositions comprising novel organofunctional polysiloxanes.
2. Description of the Prior Art
Certain types of organofunctional polysiloxanes are known in the prior art and are readily available as articles of commerce. The known organofunctional polysiloxanes are made by the reaction of poly(dimethylsiloxanes) containing SiH groups (organohydrosiloxanes) with olefinic compounds wherein the olefinic sites are allyl groups. The general reaction whereby the novel organofunctional siloxanes are created is: ##STR1## However, the above reaction is not the sole reaction that occurs during the preparation of the adduct. It has been established that a significant percentage of the allyl groups are isomerized under the addition reaction conditions to propenyl groups. The latter react very slowly, if at all, with the siloxane hydrogen atoms of the hydrosiloxane reactant. The isomerization and failure of the propenyl group to react can be depicted by the following formula: ##STR2##
It has become accepted practice within the industry to use stoichiometric excesses (20 mole % or more) of the allyl group to insure complete reaction of all silanic hydrogen atoms. Another practice has been to scavenge the residual silanic hydrogen atoms with a reactant such as methanol or ethylene. The excess unreacted or isomerized allyl group if not removed can be present as diluent thereby reducing the potency or active concentration of the final material and most certainly requires separation procedures in order to secure a relatively concentrated or pure desired compound.
There is no prior art known regarding hydrosilation reactions of methallyl acetate or any other methallyl ester with hydrosilanes or hydrosiloxanes. The unobvious nature of the unexpectedly high yields obtained from reactions of methallyl acetate with hydrosiloxanes is accented by the low yields of corresponding products obtained from allyl acetate, isopropenyl acetate, or vinyl acetate. Both allyl acetate and isopropenyl acetate generate significant amounts of propylene (see J. Am. Chem. Soc., 79 974 (1957) in reactions with hydrosilanes or hydrosiloxanes. Vinyl acetate is reported to give a low yield of hydrosilation product in reaction with MD'M (U.S. Pat. Nos. 2,967,876 and 2,970,150). Methallyl acetate unexpectedly generates much higher yields of hydrosilation products with correspondingly lower yields of undesired by-products.
A foreign patent, Ger. Offen. No. 1,961,501 (see Chem. Abstract, 73, 78069f (1970)) to Shin Etsu of Japan, discloses that siloxanes containing polyether groups bonded to the siloxane by .tbd.SiCH.sub.2 CH(CH.sub.3)CH.sub.2 O.sub.2 CR linkages can be made by reacting chloroisobutylsilicones with sodium polyether carboxylates. That process is inferior to that of this invention due to low yields, salt formation and by-products. The process of this invention provides for high yields of novel compositions .tbd.SiCH.sub.2 CH(R.degree.)CH.sub.2 O.sub.2 CR groups where R is hydrogen or a monovalent carbon-containing substituent other than polyether, e.g., monovalent hydrocarbon.
Also, U.S. Pat. No. 3,258,477 (Example 14) discloses the addition reaction of methallyl methacrylate and triethoxysilane or tribenzoyloxysilane. No prior art is known which teaches or suggests the addition reaction of any methallyl ester or similar ester with a hydrosiloxane.
British Pat. No. 1,077,664 discloses the reaction product of MD.sub.9 D.sub.9 'M (a polyhydrosiloxane fluid in which M is Me.sub.3 SiO.sub.0.5, D is --Me.sub.2 SiO--, and D' is --MeHSiO--) and isopropenyl acetate to yield "substituted polysiloxanes used in preparing single-stage polyether urethan foams." Experiments have indicated that such a reaction would not yield products with significant amounts of .tbd.SiCH.sub.2 CH(CH.sub.3)OAc groups.
The unexpected and unobvious features of this invention are also obtainable with unsaturated esters containing two ester groups on the same carbon atoms, e.g., methallylidene diacetate. There is no prior art known regarding the hydrosilation of methallylidene diacetate, or any other olefinically unsaturated diacylate, CH.sub.2 .dbd. C(R.degree.)CH(O.sub.2 CR).sub.2. Allylidene diacetate has been reacted with methyldiethoxysilane, according to J. Am. Chem. Soc., 79, 3073 (1957). Compositions made with methallylidene or similar diacylates, however, are novel and higher yields are obtained than with allylidene diacetate.
Reactions of methallyl chloride with methyldichlorosilane and ethyldichlorosilane are reported in Chem. Abstract 50, 13726e (1956). The reaction of methyldichlorosilane with allyl chloride using chloroplatinic acid catalyst is reported to give a 40 percent yield of chloropropylmethyldichlorosilane, while the corresponding methallyl chloride reaction yields 70 percent of chloroisobutylmethyldichlorosilane (see Chem. Abstract 54, 22328b (1960). Higher yields of expected products were reported for methallyl chloride over allyl chloride in reactions with trichlorosilane, methyldichlorosilane, and dimethylchlorosilane in J. Am. Chem. Soc., 82, 3601 (1960), and indicated for the same reaction with deuterotrichlorosilane (Cl.sub.3 SiD) in J. Am. Chem. Soc., 86, 895 (1964) (see also U.S. Pat. No. 3,686,253). The reaction of methallyl chloride with diethylmethylsilane gives 45 percent of chloroisobutyldiethylmethylsilane according to Chem. Abstracts 55, 15331c (1961). The preparation of siloxanes (as opposed to silanes) containing chloroisobutyl groups is disclosed in J. Am. Chem. Soc., 82, 3601 (1960).
There is, however, only a single reference known in the prior art which discloses reactions of hydrosiloxanes (as distinguished from hydrosilanes) with methallyl chloride. This reference, J. Org. Chem., 38, 838 (1973), discloses reactions of pentamethyldisiloxane (MM'), heptamethyltrisiloxane (MD'M), and tris(trimethylsiloxy)silane (M.sub.3 T'), with methallyl chloride with respective yields of 97 percent, 32 percent, and 14 percent of the desired hydrosilation products (i.e., the corresponding chloroisobutyl siloxanes).
While it is known that hydrosilanes give higher yields of hydrosilation products with methallyl chloride than with allyl chloride, there is no reason to assume the same relationship for reaction of hydrosiloxanes. With the exception of MM', the yields with methallyl chloride were quite low (32 percent for MD'M, 14 percent for M.sub.3 T') in the only known published examples. In the process of this invention, the unsaturated halide is added to the hydrosiloxane and higher yields of the desired product are obtained. No prior art is known which teaches the production of high yields of chloroisobutylsiloxanes by the addition of methallyl chloride to the hydrosiloxane pursuant to this invention.
Certain siloxanes containing chloroisobutyl groups are known as mentioned above and as shown in German Offen. No. 1,961,501 (Chem. Abstract 73, 78069f (1970)) and U.S. Pat. No. 3,414,604, having been prepared by cohydrolysis of the products obtained from reactions of hydrosilanes and methallyl chloride and methylchlorosilanes. Such compositions do not include chloroisobutylheptamethylcyclotetrasiloxane, i.e., D.sub.3 D'CH.sub.2 CH(CH.sub.3)CH.sub.2 Cl, which has also not been made prior to the instant invention by hydrosilation of methallyl chloride with heptamethylcyclotetrasiloxane (D.sub.3 D'). The composition D.sub.3 D'CH.sub.2 CH(CH.sub.3)CH.sub.2 Cl is novel and useful and can be made in good yields by the process of the present invention.
Methallyl carbamates and substituted methallyl carbamates also undergo hydrosilation reactions to give higher yields of desired products than do the corresponding allyl derivatives, according to the processes of the instant invention. The products are also novel compositions of matter and no prior art is known to teach or suggest them. U.S. Pat. No. 3,426,057 discloses the reaction of hydrosiloxanes with carbamates derived from allyl or methallyl alcohols and toluene diisocyanate. The preparation of both carbamates is given as examples of this patent and the hydrosilation examples include only the allyl carbamate, so that no comparison with the methallyl carbamate can be made. This invention is concerned only with O-methallyl carbamates which hydrosilate to give structures .tbd.SiCH.sub.2 CH(CH.sub.3)CH.sub.2 O.sub.2 CN .dbd.. U.S. Pat. No. 3,652,629 discloses hydrosilations of N-methallyl carbamates, which give rise to different structures, .tbd.SiCH.sub.2 CH(CH.sub.3)CH.sub.2 NRCO.sub.2 --, which clearly differ from the novel compositions of this invention.
Simple methallyl ethers also are employed pursuant to this invention in addition reaction with hydrosiloxanes. Typical of such simple methallyl ethers are methallyl methyl ether, methallyl phenyl ether, 3-methallyloxypropionitrile, and others, which when hydrosilated give rise to compounds containing .tbd.SiCH.sub.2 CH(CH.sub.3)CH.sub.2 OR groups where R is a carbon-containing substituent. According to this invention, simple methallyl ethers unexpectedly give higher yields of desired products in hydrosilation reactions than do the corresponding allyl ethers. Allyl ethers, such as those shown in U.S. Pat. No. 3,794,673, under conditions typical to hydrosilation reactions, undergo significant rearrangement to propenyl ethers which are unreactive toward hydrosilation. Methallyl ethers have been found unexpectedly to have a much lower propensity toward isomerization to relatively unreactive 2-methylpropenyl ethers, and accordingly give higher yields in hydrosilation reactions with hydrosiloxanes. Similarly, methacrolein acetals have unexpectedly been found to give higher yields than acrolein acetals and are included as a reactant in this invention. Acetals of methacrolein can be considered as methallyl ethers with two alkoxide groups on the same carbon atom. Reactions of acrolein acetals with hydrosiloxanes are disclosed in J. Org. Chem., 35, 4180 (1970).
Methacrolein-pentaerythritol condensates are disclosed in U.S. Pat. Nos. 3,381,019 and 3,513,183. The sulfate salts of the addition reaction products of these condensates and hydrosiloxanes are also disclosed in the patents which, however, fail to disclose or suggest the compositions of this invention or the methods of this invention and there is no suggestion that methacrolein-pentaerythritol is a preferred reactant or provides the advantages secured by this invention.
By way of prior art, U.S. Pat. Nos. 3,716,517 and 3,716,518 disclose hydrosilations of methallyl ethers containing two or more units derived from ethylene oxide or propylene oxide. These reactions involve hydrosilanes (as differentiated from hydrosiloxanes) and use peroxide catalysts instead of platinum catalysts used in processes of the instant invention. U.S. Pat. No. 3,258,477 shows a structure, (CH.sub.3 CO.sub.2).sub.3 SiCH.sub.2 CH(CH.sub.3)CH.sub.2 O(CH.sub.2 CH.sub.2 O).sub.4 COC(CH.sub.3) .dbd. CH.sub.2, with no working example. The same structure appears in U.S. Pat. Nos. 3,398,210 and 3,567,497.
The processes and compositions of the present invention regarding reactions of simple methallyl ethers with hydrosiloxanes are not shown in the prior art.
Hydrosilation reactions of silyl ethers (i.e., .tbd.SiOC.tbd.) of allyl or methallyl alcohols do appear in the prior art. For example, U.S. Pat. No. 2,898,361 discloses the respective reactions of the trimethylsilyl ethers, (CH.sub.3).sub.3 SiOC.tbd., of allyl or methallyl alcohols with tetramethyldisiloxane. There is no indication that a higher yield was obtained with the methallyl ether, and the primary examples used the allyl ether. It appears from this patent that the methallyl silyl ethers offer no advantage.
Similarly, U.S. Pat. No. 3,622,609 discloses the respective reactions of allyl or methallyl alcohols with dimethylchlorosilane to form the dimethylsilyl ethers. These, on treatment with platinum catalysts, form linear polymers, which hydrolyze and condense to form the same product claimed in U.S. Pat. No. 2,898,361 above. Again, no advantage for using methallyl over allyl was noted in the patent, although one should have been very apparent, if obtained. The latter two examples of prior art differ from the processes and products of the instant invention, which is not concerned with silyl ethers of methallyl alcohol.
There do not appear to be any reactions between hydrosiloxanes and methallyl cyanide disclosed in the prior art. Methallyl cyanide does react with hydrosiloxanes to provide higher yields than does allyl cyanide. U.S. Pat. Nos. 3,347,895 and 3,358,009 disclose gamma-cyano-gamma-methyl-butyl groups without specifying how, if at all, they are bonded to silicon and fail to disclose methallyl cyanide or any derivatives thereof. Both patents as well as U.S. Pat. No. 3,642,851 disclose the 3-cyanopropyl group but fail to disclose or suggest the methallyl derivatives disclosed and claimed herein.
No prior art is known to exist regarding reactions of methallyl alcohol with hydrosiloxanes which give higher yields than reactions of hydrosiloxanes and allyl alcohol. Compounds with .tbd.SiCH.sub.2 CH(CH.sub.3)CH.sub.2 OH groups have been prepared by hydrosilation and subsequent hydrolysis of methallyl silyl ethers as shown by U.S. Pat. Nos. 2,898,361 and 3,622,009. The direct hydrosilation of methallyl alcohol is novel and patentable as are the resultant compositions. U.S. Pat. No. 2,888,454 discloses the thermal decomposition of M.sub.2 D'(CH.sub.2).sub.3 OH by loss of Me.sub.3 SiOH and formation of cyclic disiloxane derivative. The same reaction occurs with M.sub.2 D'CH.sub.2 CH(CH.sub.3)CH.sub.2 OH, prepared in the instant invention, and at significantly lower temperatures.
Three different groups, V. F. Mironov and A. D. Petrov in Russia, J. W. Curry from Dow Corning, and K. Kojima in Japan, have published work on polymers prepared from unsaturated silanes, or from dihydrosilanes and diolefins. The Russian work in particular mentions polymerization of methallylsilanes and allylsilanes, with no advantage (e.g. the obtaining of higher molecular weight polymers) noted for methallylsilanes. The present invention is not concerned with methallylsilanes, but this prior art does confirm the unexpected nature of the present invention in the attainment of higher yields with methallyl compounds, since "dimethyl(2-methally)silane scarcely polymerizes at all", when treated with platinum catalyst (see Chem. Abstract, 54, 1271b (1960)) for abstract of Russian paper).
U.S. Pat. No. 3,632,715 discloses compounds containing .tbd.SiCH.sub.2 CH(CH.sub.3)CH.sub.2 SH groups, with which the instant invention is not concerned. The prior art has failed to recognize, the unobvious and unexpected advantages to be gained from the use of methallyl compounds in addition reactions with hydrosiloxanes. Furthermore, allyl phenyl selenide is reported to give a higher yield of product in reaction with triethylsilane than does methallyl phenyl selenide (see Chem. Abstract, 84, 164921m (1976)) which would discourage the substitution of methallyl compounds for allyl compounds in reactions of this kind.
It is shown hereinbelow that the addition of hydrosiloxanes to organic compounds having the formula EQU CH.sub.2 .dbd. C(R.degree.)CH.sub.3-m X.sub.m
wherein X is a functional group and R.degree. is a monovalent hydrocarbon group as more fully described hereinbelow instead of allylic compounds unexpectedly results in higher yields of more highly concentrated desired organofuncational polysiloxanes. Such higher yields are believed to be due to no, or only slight, isomerization of the group EQU CH.sub.2 .dbd. C(R.degree.)CH.sub.3-m
to unreactive species during hydrosilation such as usually occurs in the case of the allylic compounds.